docs: def create_from_item(cls, amount, item_description, **kwargs):
          '''
          Creates an Invoice as well as a single associated InvoiceItem
          with the passed description (for things like gift certificates)
          '''
          submissionUser = kwargs.pop('submissionUser', None)
          collectedByUser = kwargs.pop('collectedByUser', None)
          calculate_taxes = kwargs.pop('calculate_taxes', False)
          grossTotal = kwargs.pop('grossTotal',None)
  
          new_invoice = cls(
              grossTotal=grossTotal or amount,
              total=amount,
              submissionUser=submissionUser,
              collectedByUser=collectedByUser,
              buyerPaysSalesTax=getConstant('registration__buyerPaysSalesTax'),
              data=kwargs,
          )
  
          if calculate_taxes:
              new_invoice.calculateTaxes()
  
          new_invoice.save()
  
          InvoiceItem.objects.create(
              invoice=new_invoice,
              grossTotal=grossTotal or amount,
              total=amount,
              taxes=new_invoice.taxes,
              description=item_description,
          )
          return new_invoice